A packet transport network (Packet Transport Network, PTN for short) of a communication system uses a link formed by network element nodes to transmit a data packet of a service. To avoid that failure of a part of nodes or links affects service transmission, an automatic protection switching (Automatic Protection Switching, APS) technology is put forward in an existing PTN. That is, a service on a faulty link is switched to a preset standby link for transmission, thereby not affecting service transmission.
Microwave is a type of transmission medium between nodes on a link, and currently is widely applied in an operator network. The synchronous digital hierarchy (Synchronous Digital Hierarchy, SDH for short) technology and the plesiochronous digital hierarchy (Plesiochronous Digital Hierarchy, PDH for short) technology are much more commonly used, and an E1 service is mainly transmitted. In recent years, an IP service gradually replaces the E1 services, and occupies most of traffic in the network, and the requirement for bandwidth sharply increases. Under such circumstances, since traditional PDH and SDH microwaves cannot well support the IP service, the PDH and SDH microwaves are gradually replaced by a packet microwave technology. A microwave link has a relatively special attribute, which is called adaptive modulation (Adaptive Modulation, AM for short). A node that transmits data based on the microwave may change the modulation mode automatically according to the change of current environment. This may lead to the bandwidth change of the microwave link, but may ensure a low bit error rate of service transmission.
During the study of the present invention, the inventor finds that applying the APS technology in a PTN network that includes a microwave link has the defects as follows. For the existing APS technology, in normal case, a protected service is transmitted on a working path, and an unprotected service or no service is transmitted on a protection path; when a failure occurs, all protected services are switched to the protection path for transmission. However, in one aspect, due to the AM feature, a microwave link can still transmit a part of services after the bandwidth is adjusted, and service switching may lead to packet loss, which deteriorates service transmission efficiency and service quality; in another aspect, if the microwave link exists on both the working path and the protection path, and the bandwidth on the protection path also decreases, probably the bandwidth requirement of all switched services cannot be met.